The invention relates to a method for cultivating crop plants having a shoot-root plant body, wherein during growing, part of the stem is prepared such that new roots grow on the stem part. The new roots are brought into contact with a growth medium, such that during production of the crop, the stem length between the shoot furthest from the roots and the roots in contact with the growth medium and closest to the shoot is maintained at a relatively short length as compared to a normal length of the plant of the same age. The crop plants include, but are not limited to, tomatoes, cucumbers, egg-plants, peppers and other known plants.
French patent application FR 2 769 463 discloses a method for growing palm trees, in which each palm tree is allowed to grow to a relatively large height. After this growth, a collar is provided around the stem of the palm tree very close to the leaves and coconuts far away from the ground where the original roots of the palm tree grow. New root growth is stimulated in the collar. Once new roots have sufficiently grown, the stem is cut between the old roots and the new roots after which the old roots, with the long stem attached thereto, are excavated and discarded. After the old roots are excavated and discarded, the procedure is repeated.
Dutch Patent NL 1 007 449 discloses a method for growing crops wherein the crops are grown from substrate troughs filled with a growth medium. The troughs are height adjustable and suspended from an adjustable suspension means. Stems of the plants are tied up, for instance, by a wire attached to the upper ends of the plants after the plants reach a certain length. After crops are harvested from a lower end of the plant, the plant is lowered by lowering the wire a certain distance.
Crop plants with a shoot-root plant normally grow from the top wherein the crop grows near the top of the plant. Once the crop has grown on part of the plant and has been harvested, the crop-bearing part of the plant will not bear further crop. Crop plants having a shoot-root plant body can grow to great length, for example over 15 m for tomatoes or even over 30 m for cucumbers. The disadvantage is that the distance between the top of the plant, where the crop grows, and the roots, near the bottom of the plant, becomes large. This results in an increasing distance over which nutritious substances travel from the roots to the crop located near the top of the plant and results in smaller crops.
The present invention relates to a method for cultivating crop plants, in which the disadvantages of known methods are eliminated. To this end a method according to the present invention is includes preparing part of the stem of the plant such that new roots grow on the part of the stem during growth, positioning the growing plant such that the new roots are brought into contact with a growth medium, wherein during production of the crop, a length of the stem between the shoot located furthest from the roots and the roots in contact with the growth medium closest to the shoot is maintained at a relatively short length as compared to a normal stem length of a plant of a similar age and wherein the plant body is suspended, at least partly, from its top.
Suspension of the top of the plant from a suspension means, such that the top part of the plant, more particularly the part of the crop growing part of the plant, extends substantially vertically such that relatively little space is necessary for the plant, whereas proper use can be made of the available light. In a method according to the invention, the plant length is controlled such that the distance between the crop growing part of the plant and the roots in contact with growth medium is maintained at a relatively small distance. Preferably the stem length is kept substantially constant during the life cycle of the crop plant.
By keeping the stem length relatively small, the nutritious materials are transported over a small distance during the life cycle of the crop plant such that optimal crop yields may be harvested during relatively long periods of time. In known methods of cultivating crop plants, the crop plants are removed and replaced by new, young plants after a couple of months since the yield and quality of the crop becomes insufficient. In a method according to the present invention, the life cycle of the plant is extended up to one, or even several years, during which time the yield and quality of the crop is substantially constant and high. A further advantage of a method according to the invention is that the overall length of the plant will remain relatively short during the life cycle thereof. The basically useless or unfavorable part of the stem located between the roots in contact with the growth medium and the crop growing part of the plant, on which part of the plant no crop grows and is normally about several meters long, is kept short. Therefore, the part does not obstruct passage ways, floor space or occupy other room around the plant and enables easier harvesting of the crop.
Preparing part of the stem for new roots to grow thereon is to be understood in this application as at least meaning positioning the stem part in or on growth medium, such as water, earth, glass-wool, rock-wool or similar growth medium. The stem part can also be mechanically and/or chemically treated by any known means to initiate or accelerate root growth.
In one embodiment, a method according to the present invention includes preparing part of the stem of the plant such that new roots grow on the part of the stem during growth, positioning the growing plant such that the new roots are brought into contact with a growth medium, wherein during production of the crop, a length of the stem between the shoot located furthest from the roots and the roots in contact with the growth medium closest to the shoot is maintained at a relatively short length as compared to a normal stem length of a plant of a similar age and wherein the plant body is suspended, at least partly, from its top, and wherein the stem part on which the new roots are grown is positioned substantially horizontal and at least, part of the roots distanced from the shoot is positioned at a level higher than, at least, part of the roots, especially higher than the stem part on which the new roots are grown.
Positioning the stem part of the plant substantially horizontally on which the new roots grow has the advantage that the stem part can relatively easily be brought into contact with growth medium, such as water, over a relatively large length. Surprisingly, root growth on the stem part is improved and accelerated by positioning at least part of the existing roots at a level higher than at least part of the stem part on which the new roots are grown. By positioning the root part higher than the stem part on which new roots are to be grown, the normal equilibrium of at least hormones in the crop plant is disturbed such that a lesser amount of root growth inhibiting hormone is transported to the stem and/or more root growing hormone is transported in the direction of the stem part next to the roots for initiating or accelerating root growth thereon. It is believed that auxins contribute to this effect. This effect may be further enhanced by providing a means for blocking root growth on the roots distanced from the part of the plant that the new roots are growing on. This can be obtained by bringing the roots out of contact with the growth medium, by at least partly cutting the roots or any other means of blocking root growth known in the art.
In another embodiment of the present invention, a method includes suspending the top of the plant from a suspension means, periodically lowering the top of the plant such that the plant can grow back up again along the suspension means and wherein during or subsequent to the lowering of the top of the plant, the roots are at least partially retracted in a direction away from the top of the plant a similar distance such that new roots are grown and/or become in contact with the growth medium.
Suspension of the top of the plant from a suspension means such that the top part, more particularly part of the crop growing part, of the plant extends substantially vertically means that relatively little space is necessary for the plant and proper use can be made of the available light. By periodically lowering the top of the plant such that it can grow back on again, meanwhile retracting the roots, at least partly, in a direction away from the top of the plant, a stem part located near, or preferably adjacent, the roots can be brought into contact with growth medium such that new roots can grow on the stem part. In this manner, at least part of the older roots can be brought out of contact with the growth medium.
In this way, the stem length between the roots in contact with the growth medium and the crop growing part of the plant can be regulated during use and be kept at a relatively short and, preferably, substantially constant length. The stem part of the plant on which the roots are to be grown are preferably brought into contact with growth medium in a receiving means. It should be clear to any person skilled in the art that the roots are to be moved relative to the growth medium wherein the receiving means, the growth medium and thus the roots, or both can be moved. It is equally possible to position new growth medium along a part of the stem on which roots are to been grown, after which the growth medium together with the stem part can be retracted.
In another embodiment of the present invention, the method includes positioning the stem part next to the part of the plant on which new roots are grown substantially horizontally and is bearing crop close to harvesting, the crop being suspended substantially vertically from the stem part.
By positioning the crop carrying part of the plant, of which the crop is close to being harvesting, substantially horizontally by suspension, the crop is suspended substantially vertically downward, meaning that the crop can easily be harvested, for example by a (robotic) means, which are placed under the stem part.
In one embodiment, guide means are used, such as a wire; which enables easy movement of the plant, as well as guidance thereof. Clamping means may also be used to connect the plant to the guide means, such that the plant can easily be repositioned along the guide means.
It is preferred that in a method according to the present invention, the roots are bred on water, such as in a tidal system. This has the advantage that the roots and/or the adjacent stem part can easily be moved along the growth medium. Moreover, such growth medium enables easy excess, proper nutrition and other known advantages.
In a method according to the present invention at least part of the root bearing part of the plant can be cut off. This means that the overall length of the plant can be kept relatively short.
The present invention further relates to a device for cultivating crop bearing plants, including a means for receiving at least part of a root bearing part of the plant body, wherein the means for receiving is configured for moving or allowing movement of at least part of the stem of the plant into the means for receiving during growth of the plants and wherein the means for receiving is further configured for inducing or expediting root growth on at least part of the stem.
With a device of the present invention, crop bearing plants with a shoot-root plant body can be easily cultivated wherein during growth, the plants stem length between a crop growing part of the plant and the nearest roots of the plant in contact with growth medium can be kept at a relatively short length. This has the advantage that optimal use can be made of nutrients in crop growing.
The invention further relates to a device and a crop growing plant, wherein the root bearing part of the crop growing plant is at least partly positioned in the means for receiving, a suspension means configured for suspending part of the stem having shoots next to the top of the plant; and wherein at least part of the stem bearing crop, at least substantially ready for harvest, extends substantially horizontally.
By positioning the root bearing part of the plant in the receiving means, part of the stem having shoots near to the top of the plant that are suspended substantially vertically from the suspension means has the advantage that relatively little space is necessary for growth of the plant. In this manner, a relatively large part of the stem on which the roots are to be grown can be brought into contact with growth medium, even if the latter is mainly water. Positioning the crop bearing part of the bearing crop, at least substantially ready for harvest, substantially horizontally has the advantage that this crop can easily be harvested.
The present invention further includes a warehouse including a suspension means positioned above the floor of the warehouse for suspending the plants and a root growing means configured such that the root bearing part of each plant is to be cultivated, at least partly, substantially horizontally and for moving the root bearing part through the root growing means.
In one embodiment, the warehouse further includes a lighting means positioned in the warehouse such that during use, the lighting means extends substantially above the crop bearing parts and the flowering parts of the plants.
By positioning lighting means in the warehouse substantially above the crop bearing and/or the flowering parts of the plants, sufficient light can be provided to the plants. Using a method according to the present invention and devices according to the present invention, the overall height of the plant above the floor of the warehouse can be kept relatively small and constant, such that positioning of the lighting means is possible.
The invention further includes a method for grafting crop plants including positioning a shoot of a crop growing plant substantially horizontally in a receiving means, such that at least one leaf of the plant extends outside the receiving means and wherein the shoot is brought into contact with a growth medium inside the receiving means for growing roots on the shoot.
Using shoots of a crop growing plant for grafting crop plants has the advantage that substantially the same plants can be obtained having the desired characteristics of the crop growing plant.